selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/reset/amlogic/reset-meson-aux.c b/drivers/reset/amlogic/reset-meson-aux.c
new file mode 100644
index 000000000..33c060134
--- /dev/null
+++ b/drivers/reset/amlogic/reset-meson-aux.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * Amlogic Meson Reset Auxiliary driver
+ *
+ * Copyright (c) 2024 BayLibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
+#include "reset-meson.h"
+
+static const struct meson_reset_param meson_a1_audio_param = {
+	.reset_ops	= &meson_reset_toggle_ops,
+	.reset_num	= 32,
+	.level_offset	= 0x28,
+};
+
+static const struct meson_reset_param meson_a1_audio_vad_param = {
+	.reset_ops	= &meson_reset_toggle_ops,
+	.reset_num	= 6,
+	.level_offset	= 0x8,
+};
+
+static const struct meson_reset_param meson_g12a_audio_param = {
+	.reset_ops	= &meson_reset_toggle_ops,
+	.reset_num	= 26,
+	.level_offset	= 0x24,
+};
+
+static const struct meson_reset_param meson_sm1_audio_param = {
+	.reset_ops	= &meson_reset_toggle_ops,
+	.reset_num	= 39,
+	.level_offset	= 0x28,
+};
+
+static const struct auxiliary_device_id meson_reset_aux_ids[] = {
+	{
+		.name = "a1-audio-clkc.rst-a1",
+		.driver_data = (kernel_ulong_t)&meson_a1_audio_param,
+	}, {
+		.name = "a1-audio-clkc.rst-a1-vad",
+		.driver_data = (kernel_ulong_t)&meson_a1_audio_vad_param,
+	}, {
+		.name = "axg-audio-clkc.rst-g12a",
+		.driver_data = (kernel_ulong_t)&meson_g12a_audio_param,
+	}, {
+		.name = "axg-audio-clkc.rst-sm1",
+		.driver_data = (kernel_ulong_t)&meson_sm1_audio_param,
+	}, {}
+};
+MODULE_DEVICE_TABLE(auxiliary, meson_reset_aux_ids);
+
+static int meson_reset_aux_probe(struct auxiliary_device *adev,
+				 const struct auxiliary_device_id *id)
+{
+	const struct meson_reset_param *param =
+		(const struct meson_reset_param *)(id->driver_data);
+	struct regmap *map;
+
+	map = dev_get_regmap(adev->dev.parent, NULL);
+	if (!map)
+		return -EINVAL;
+
+	return meson_reset_controller_register(&adev->dev, map, param);
+}
+
+static struct auxiliary_driver meson_reset_aux_driver = {
+	.probe		= meson_reset_aux_probe,
+	.id_table	= meson_reset_aux_ids,
+};
+module_auxiliary_driver(meson_reset_aux_driver);
+
+MODULE_DESCRIPTION("Amlogic Meson Reset Auxiliary driver");
+MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_IMPORT_NS("MESON_RESET");